Abstract: The invention relates to a procedure for chemically determining the base sequence of DNA and, in particular, its step of cleaving the labeled DNA having undergone a base-selective chemical modification at the position of the modified base. More particularly, it relates to a method for cleaving DNA which comprises modifying DNA base-selectively with chemical reagents, bringing the resulting reaction mixture into contact with an adsorbent to adsorb the chemically modified DNA on the adsorbent, washing the adsorbent with a washing fluid to remove any chemical modification reagents from the adsorbent, bringing the adsorbent into contact with an eluent to elute the chemically modified DNA adsorbed thereon, concentrating the resulting eluate and then heating it together with a cleavage reagent.

Abstract: The present invention provides thiazolyl derivatives as new chemical substance represented by the general formula: ##STR1## wherein R.sup.1 stands for a lower alkyl group or a substituted or unsubstituted phenyl group, R.sup.2 for a hydrogen atom, a lower alkyl, lower alkoxy or lower alkylthio group, and R.sup.3 for a pyridyl or iso-oxazolyl group or a grouping of the general formula: ##STR2## processes for preparing same and pharmaceutical compositions containing the thiazolyl derivatives. More particularly, the present invention provides new thiazolyl derivatives which possess immuno-modulating activity and are thus therapeutically effective against immunodiseases such as chronic rheumatoid arthritis and also useful against viral diseases or for the immunotherapy of cancers and possess properties desirous as medicines with a slight toxicity, processes for preparing same and pharmaceutical compositions containing the new substance.